The B1C signal adopts a new navigation signal system including pilot and data signal. These two signals are transmitted simultaneously in an orthogonal manner. When the signal is weak, two signals need to be processed jointly to improve the signal detection ability. This paper designs a novel weighted joint acquisition algorithm. Monte Carlo simulation has been done to evaluate the performance. The simulation results show that the detection performance of the proposed algorithm connects with the weighted coefficient. When the optimal weighting coefficient is selected, detection performance can be improved greatly under the condition of weak signal. Keywords: B1C signal, weighted joint acquisition algorithm, weighted coefficient.

A systems engineering approach to master measurand lists allows the use of metadata to improve data organization and management. As data acquisition systems become more complex, the management of sensors and their measurands must also advance. Traditional tabulated measurand lists of several hundred measurands are typically generated from email or verbal requests. Modern data acquisition systems with thousands of measurands are more complex than ever, causing these tabulated spreadsheets to become unwieldy and unmanageable. Modern data structures can easily organize and archive these lists through measurand metadata. By aligning the requirements of the measurand database with data acquisition system requirements, designers can ensure their data acquisition system is within constraints such as bandwidth, storage capacity, power consumption, size, and weight.

Previous work modeled the cruise phase of an aeronautical channel and showed how the channel varied as a function of height, distance, and speed. What was apparent from that analysis was that the ``cruise" channel was remarkable stable and varied slowly and predictably over time. The steady state channel reflected a 2-ray multipath model which exhibits deep nulls in the spectrum which affects serial tone modems significantly. Further the application of parallel tone modulation improves performance except for that portion of the band which was degraded by the null. This points to the use of Adaptive OFDM (AOFDM) structure wherein tones are only sent in portions of the band which are strong and not areas where the signal is weak. This work develops a method for capturing a profile of the Signal to Distortion Ratio (SDR) for each tone for each frame and over time. It also develops a method for converting the SDR per tone to estimate the optimum QAM modulation scheme for each tone for application in Link Dependent Adaptive Radio (LDAR).

The continual advances in military system technologies compel the Test & Evaluation community to constantly mature and adapt test methodologies and instrumentation capabilities. The need for alternate approaches aimed at collecting in-flight missile Time Space Position Information (TSPI) that compliment on-system high dynamic GPS and radar is just one example that supports the development of new techniques and numerical methods. The primary objective of this technical paper is to provide conceptual details pertaining to a methodology that can determine a TSPI solution based on telemetry signal strength or data arrival time combined with the Newton-Raphson Jacobian method for solving a multivariate system of equations.

For decades, analog amplitude modulation (AM) imparted by antenna feeds has served as the gold standard by which antenna control units (ACUs) manage tracking. This paper presents a digital alternative, designed to provide AM information, signal quality metrics, and additional real-time status, all over existing analog AM cables. Its benefits include reduced (and known) delay in the tracking loop, smart selection among multiple tracking receivers, and support for advanced features such as tracking through interfering signals and tracking intermittent or time-division-multiplexed transmissions.

BER is regarded as the link-performance metric in a digital communication system. It is a function of Eb/N0 and is dependent on the modulation scheme used. This relation is often used in prediction of ground telemetry systems performance for a mission configuration. However, there is no objective way of comparing the post flight results, as BER measurement in a flight test is not practically feasible for want of transmitting sufficient reference bit patterns. In this paper, an indirect way of computing BER and, in turn, link Eb/N0 is proposed for a PCM/FM link based on the frame synchronised data logged by the ground telemetry equipment. Using known quantities like bit rate and frame rate, a quantity defined as frame loss rate is computed. Applying the relations between frame loss probability, frame sync pattern and SFID information in the PCM format, an approach for bit error probability is demonstrated based on field data. By using a sliding window over a fixed length of data, BER for the entire flight duration can be determined as a function of flight time with the step size of the length of data window.

Chapter 7 of IRIG106-17 defines the means of encapsulating packetized data within a PCM telemetry stream, ostensibly for transport from a platform to a processing location, via that platform’s conventional means of PCM transmission. While providing a mechanism for bridging platforms via the telemetry stream, a myriad of use-cases evolve, adding varying degrees of complexity to an implementation. Understanding these use-cases, their challenges, and some of the potential solution methodologies helps to determine the best implementation for a given mission. This paper seeks to present some of these aforementioned points, some obvious, and others uncovered over the course of working with solutions-seekers, in an effort to help cultivate and shape the growing demand for packet telemetry transport bridging.

We present a modified belief propagation (BP) algorithm for decoding low density parity check codes having graphs with short cycles. The modified algorithm in log domain is superior in terms of numerical stability, precision, computational complexity and ease of implementation when compared to the algorithm in the probability domain. Simulation results show improvement in decoding performance for the modified BP compared to the original algorithm. The modified approach is also generalized for graphs with isolated cycles of arbitrary length by considering the statistical dependency among messages passed in such cycles.

The RCC Telemetry group publishes various documents and IRIG-106 aims to standardize telemetry solutions. Such efforts help to ensure that ranges - and other flight test users - have access to a range of interoperable equipment. The standard is updated every two years with the latest version being IRIG-106-17. The release of IRIG-106-17 means flight test engineers now have a new list of transmitter performance features to understand and to track during the daily operations. This paper provides an overview of these new features as well as the associated command structure as published in the standard.

As part of a student-educational experience in telemetry, beginning undergraduates build, program, and test small payloads flown in model rockets. These payloads, nicknamed “femtosats,” collect and transmit real time telemetry on the rocket’s performance. The femtosats measure the inertial motions of the model rocket, providing info to extract the flight path. The individually student-designed femtosat circuit board includes a simple inertial measurement sensor that collects acceleration data in the form of x, y, z acceleration vectors which are transmitted in real-time to a radio ground station. The focus of this paper is the collection and analysis of the data from the telemetered inertial measurement sensor and how it can be interpreted and applied in simple model rocket motion analysis.

This paper describes a module used to provide autonomous navigation and obstacle avoidance to a teleoperated prototype Mars rover designed to compete in the 2019 University Rover Challenge. For the competition’s Autonomous Traversal task, the rover must be capable of traversing difficult desert terrain in search of visual waypoints. Our design uses a custom Navigation Board (NavBoard), a mobile robotics computer, and a sensor capable of producing a dense point cloud. NavBoard provides quaternion-based orientation data, distance measurements from a 1D LiDAR system, and GPS data over ethernet to a mobile robotics computer. This computer derives a 3D point cloud from a three-headed collinear stereoscopic camera then processes that data along with the data from NavBoard to determine the correct action to navigate through sparsely mapped terrain.

This paper presents the implementation of a standard PLL-based timing and phase synchronization system on hardware usingan FPGA. The synchronization system is shown to successfully recover a 16-APSK signal despite off sets in phase and frequency between the transmitter and receiver local oscillators. Furthermore, it is shown that system performance, in terms of symbol times required to achieve lock, is comparable to double-precision floating point simulations despite using fixed point numbers with as few as 5 fractional bits for most computations.

Mature companies implement robust cybersecurity practice in their organizations by deploying a layered defense comprising many differing security tools whose functionality complements one another. Tools such as firewalls, Anti-Virus (AV), Intrusion Detection/Prevention (IDS/IPS), Data Leak Protection (DLP), and Security Information and Event Management (SIEM) can be rolled out in many combinations to create very effective cyber defenses. A general premise is that organizations are trying to keep “bad guys” out. In recent years, focus has been shifting to address the potential for malicious (insider) employees who may wish to take actions to compromise the firms they work for as an increasing number of incidents are attributed to insiders. After reviewing the insider threat landscape as well as accepted methodologies for detection; application to telemetry post processing environments will be discussed with example deployment scenarios explored.

High-precision location of space launch vehicles is a key component of the flight safety. The need for a very accurate location has gained the whole launch with the flight and re-entry stages being also critical in terms of safety. Thanks to the hybridization of GNSS and INS data, the accurate location can be fully defined inside the launch vehicle at low cost. This opens up to the setting of an autonomous system for location on-board the vehicle. Still, in order to ensure the reliability of such a system, many redundancies have to be set which implies to add equipment: autonomous power, processing, unique telemetry downlink... Adding this equipment challenging in an environment where the use of room and the adding of weight are very tightly monitored. This paper describes the techniques to settle a fully autonomous location system which answers to the needs for an accurate, strongly reliable location while being non-intrusive, cost-effective and easily integrated in any launch vehicle.

Spatial modulation techniques have the ability to convey information by both the positions of active antennas as well as the symbols they transmit. Such techniques include the generalized spatial modulation (GSM) that can provide high spectral efficiency. In general, however, the total number of available symbols in GSM is not a power of two. Therefore, selection of a symbol alphabet from the available symbols is needed. This is a numerically complex problem. In this paper, we propose to significantly reduce the complexity of the GSM symbol set selection problem by grouping antennas together to form blocks, thus producing block GSM (BGSM) symbols. A previously developed iterative combinatorial method is extended to BGSM symbol selection. The effects of the Rician K-factor, BGSM symbol block size, and antenna configuration on the performance and design complexity are studied. The algorithm is found to significantly reduce the complexity of the BGSM symbol set selection problem.

Software defined radios are rapidly increasing in both research and commercial usage for many different applications. As the number of deployed systems increase, a difficult problem that remains is efficient usage of the Radio-Frequency (RF) spectrum to be shared among all these devices. Two key tasks for the radio to perform here include spectral estimation of the RF environment and channel estimation of the communication channel for which the data will be transmitted. These two steps are linked as the communication channel can change over different portions of the RF-spectrum. In this work, an algorithmic approach is presented for passive and active channel estimation procedures for wideband software-defined radios. The algorithm is comprised of first channel quality estimation followed by communication channel planning to optimize the overall performance.

Gaussian process (GP) regression can be used in the interpolation of observed periodic channel estimates in OFDM transmission systems over both time and frequency in small-scale fading environments. Previous GP regression studies used the popular radial basis function as the GP kernel. In this study, we examine the performance of GP regression using a Bessel kernel with a semi-static hyperparameter vector. Results show that GP regression using the Bessel kernel outperforms the radial basis kernel, as well as traditional interpolation methods such as cubic spline and FIR interpolation, especially when training symbols are spaced far apart in time with respect to the channel coherence time.

Dynamic spectrum allocation (DSA) permits unlicensed users to access spectrum owned by a licensed user given they do so without interference to the primary user. To avoid interference with other users, the unlicensed user needs to be aware of channel availability. Spectrum sensing allows a radio to find spectrum holes, but costs energy and time. Predictive methods can be used to decrease the amount of spectrum sensing needed to find an available channel. We designed a novel neural network architecture for spectrum hole prediction. This neural network is capable of creating probability mass functions (PMF) estimates of the length of channel openings with no assumptions of the initial probability distribution or prior knowledge about the traffic. This architecture is shown to work through a mathematical proof, and its performance is measured through simulation.

This paper analyzes the effect of Long-Term Evolution (LTE) uplink interference on the performance of Aeronautical Telemetry S-band users. A MATLAB simulation environment is used to analyze the interference effect using SOQPSK-TG and 64-QAM modulation schemes for telemetry and LTE transmitters, respectively. An ideal Surface Acoustic Wave (SAW) filter followed by a 2-by-2 symbol detector is used in the telemetry receiver. To ensure a target bit error rate (BER) of 10-5, depending on the LTE spectrum mask, the Carrier-to-Interference (C/I) ratio requirement is -15.4, -32.4 and -30 dB for data rates 1; 5 and 10 Mbits/s, respectively.

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